:root {
  --color-putty: #c4c3b6;
  --color-ink: #000000;
  --color-bone: #e7e5e4;
  --color-chalk: #ebebeb;
  --color-vellum: #dfdcd5;
  --color-graphite: #4b4a48; /* I-1 fix: 加深使 putty 底上 AA≥4.5（#595855 约 4.0:1 → #4b4a48 约 5.0:1） */
  --color-ash: #808080;
  --color-paper: #ffffff;
  --font-serif-cn: "Noto Serif SC", "Source Han Serif SC", "SimSun", serif;
  --font-sans: Inter, "Helvetica Neue", Arial, sans-serif;
  --radius-cards: 9px;
  --radius-buttons: 28.8px;
  --radius-links: 2px;
  --ease: cubic-bezier(0.32, 0.72, 0, 1);
  --pad-x: clamp(24px, 6vw, 96px);
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-snap-type: y proximity; } /* proximity：JS 缓动翻页落位不被强制吸附干扰，触屏仍可自然吸附 */
body {
  background: var(--color-putty);
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; }

.page {
  min-height: 100vh;
  min-height: 100dvh;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: clamp(88px, 14vh, 140px) var(--pad-x);
  position: relative;
}
.page-light { background: var(--color-putty); color: var(--color-ink); }
.page-dark  { background: var(--color-ink);  color: var(--color-paper); }
.page-chalk { background: var(--color-chalk); color: var(--color-ink); }

.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  display: flex; justify-content: space-between; align-items: center;
  padding: 16px var(--pad-x);
  background: transparent; /* 无玻璃拟态、无底色：直接叠在明暗屏上 */
}
/* Task 6 Step 1 header 明暗收口 —— 方案A（启用）：显式反白。
   header 继承 body 的 ink 文字，明屏（putty）上默认可读；
   暗屏（绘画/书签/首饰）经 body[data-page]（JS 判屏写入）显式反白为 paper。 */
body[data-page="painting"] .site-header,
body[data-page="bookmark"] .site-header,
body[data-page="jewelry"] .site-header { color: var(--color-paper); }
/* 二选一依据（弃用方案B mix-blend-mode: difference）：header 文字为纯黑 ink，
   对 putty(#c4c3b6) 与 ink(#000) 背景做 difference 均≈背景色 → 明暗屏都不清晰；
   需 header 改白字方可成立，观感风险高故不启用。
   方案B（备选，仅当 header 改白字后可恢复）：
   .site-header { mix-blend-mode: difference; color: var(--color-paper); } */
.site-logo {
  font-family: var(--font-serif-cn); font-size: 1.1rem;
  text-decoration: none; letter-spacing: 0.2em;
}
.site-nav { display: flex; gap: 20px; }
.site-nav a {
  font-size: 0.72rem; letter-spacing: 0.2em; color: inherit;
  text-decoration: none; border-bottom: 1px solid transparent;
  transition: border-color 400ms var(--ease);
}
.site-nav a:hover, .site-nav a.is-current { border-bottom-color: currentColor; }

.page-hero { justify-content: center; }
.eyebrow { align-self: flex-start; font-size: 0.62rem; letter-spacing: 0.35em; color: var(--color-graphite); margin-bottom: 24px; }
.hero-name {
  font-family: var(--font-serif-cn);
  font-size: clamp(6rem, 24vw, 26rem);   /* 首屏左右均超宽 → 裁切出屏 */
  line-height: 0.84;
  letter-spacing: -0.04em;               /* 中文紧排负字距 */
  font-weight: 500;
  white-space: nowrap;
  margin-left: calc(var(--pad-x) * -1);  /* 负外边距抵消容器 padding，让字真正顶到视口边缘 */
}
.hero-tagline { margin-top: 32px; max-width: 24em; color: var(--color-graphite); }
.scroll-hint { position: absolute; bottom: 36px; left: 50%; transform: translateX(-50%); animation: hint 2.4s var(--ease) infinite; }
@keyframes hint { 0%, 100% { opacity: .35; transform: translate(-50%, 0); } 50% { opacity: 1; transform: translate(-50%, 8px); } }
@keyframes popIn { from { opacity: 0; transform: scale(.92); } to { opacity: 1; transform: scale(1); } }

.page-label {
  position: absolute; top: clamp(88px, 14vh, 140px); left: var(--pad-x);
  font-family: var(--font-serif-cn); font-size: clamp(1rem, 2vw, 1.4rem);
  letter-spacing: 0.08em;
}
.page-label .num { font-size: .72em; color: var(--color-graphite); margin-right: .6em; }
.page-label .count { font-size: .72em; color: var(--color-graphite); font-family: var(--font-sans); letter-spacing: .15em; }
.page-dark .page-label .num, .page-dark .page-label .count { color: var(--color-paper); }

.carousel {
  position: relative;
  display: flex; align-items: center; gap: 12px;
  margin-top: clamp(48px, 8vh, 80px);
}
.carousel-track {
  display: flex; gap: clamp(12px, 3vw, 32px);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: none;               /* 隐藏滚动条，保持极简 */
  -webkit-overflow-scrolling: touch;
  padding: 8px clamp(6px, 3vw, 24px);  /* 让首/末张也能居中露出 */
  scroll-padding-inline: 20px;
}
.carousel-track::-webkit-scrollbar { display: none; }
.slide {
  flex: 0 0 auto;                      /* 宽度由图片原始比例决定，不统一矩形 */
  scroll-snap-align: center;
  max-width: min(64vw, 780px);         /* 只限宽，高度按原图比例 */
  background: none;                    /* 去掉 ash 占位背景框 */
  display: grid; place-items: center;
  overflow: hidden;
}
.slide img {
  width: auto;                          /* 宽度按固有比例随高度 */
  height: calc(100dvh - 200px);         /* 确定高度，宽随比例——盒贴合固有宽高比，不拉伸不变形 */
  max-width: 100%;                      /* 超宽横幅图兜底防溢出 slide */
  object-fit: contain;                  /* 兜底：max-width 截断时内容仍按原始比例完整显示 */
  display: block;
}
.slide.is-current img { transition: transform 700ms var(--ease); }
.slide.is-current:hover img { transform: scale(1.03); }   /* 仅 hover 轻微放大，无阴影 */

.carousel-prev, .carousel-next {
  flex: 0 0 auto; width: 44px; height: 44px;
  border: 1px solid currentColor; border-radius: var(--radius-buttons);
  background: none; color: inherit; cursor: pointer;
  font-family: var(--font-sans); font-size: 1rem; line-height: 1;
  transition: background 400ms var(--ease), color 400ms var(--ease);
}
.carousel-prev:hover, .carousel-next:hover { background: currentColor; color: var(--color-putty); }
.page-dark .carousel-prev:hover, .page-dark .carousel-next:hover { color: var(--color-ink); }

.carousel-info {
  display: flex; align-items: baseline; gap: 16px;
  margin-top: 20px;
}
.slide-title { font-family: var(--font-serif-cn); font-size: clamp(1.2rem, 2.4vw, 1.8rem); font-weight: 400; }
.slide-year { font-family: var(--font-sans); font-size: 0.78rem; letter-spacing: .15em; opacity: .6; }

.dots { display: flex; gap: 8px; margin-top: 20px; list-style: none; }
.dots button {
  width: 10px; height: 10px; border: 1px solid currentColor; border-radius: 2px; /* 方点呼应印章 */
  background: none; cursor: pointer; padding: 0;
}
.dots button.is-current { background: currentColor; }

.page-dark .slide-title, .page-dark .slide-year { color: var(--color-paper); }
.page-dark .dots button { border-color: var(--color-paper); }
.page-dark .dots button.is-current { background: var(--color-paper); border-color: var(--color-paper); }

/* Task 4: 判屏触发当前张 pop 入场（@keyframes popIn 定义见 .hero-name 上方） */
.slide-pop img { animation: popIn 500ms var(--ease) both; }

/* Task 5: lightbox 全集合（纯色遮罩，不引入渐变 / 阴影） */
.lightbox { position: fixed; inset: 0; z-index: 100; background: rgba(0,0,0,.92); display: grid; place-items: center; }
.lightbox[hidden] { display: none; }
.lightbox img { max-width: 86vw; max-height: 84vh; object-fit: contain; }
.lightbox-close, .lightbox-prev, .lightbox-next { position: absolute; background: none; border: none; color: var(--color-paper); font-size: 1.6rem; cursor: pointer; }
.lightbox-close { top: 24px; right: 28px; }
.lightbox-prev { left: 24px; top: 50%; transform: translateY(-50%); }
.lightbox-next { right: 24px; top: 50%; transform: translateY(-50%); }

/* ============ Task 6: 无障碍 / 响应式 / reduced-motion / 收口 ============ */

/* lightbox 打开时锁定背景滚动（配合 JS 对 html/body 同时加 .is-locked；
   html 根元素 overflow 影响视口滚动，故两者都锁才可靠） */
html.is-locked, body.is-locked { overflow: hidden; }

/* 窄屏（≤720px）紧凑化 */
@media (max-width: 720px) {
  .site-nav { gap: 10px; }
  .site-nav a { font-size: .62rem; letter-spacing: .12em; }
  .carousel-prev, .carousel-next { width: 36px; height: 36px; }
  .slide { max-width: 82vw; }
}

/* I-1 超宽视口（≥1650px）：轨道收窄居中，slide 宽度上限放宽 */
@media (min-width: 1650px) {
  .carousel { max-width: 1200px; margin-inline: auto; }
  .slide { max-width: min(44vw, 640px); }
}

/* reduced-motion：全关闭动画/过渡/平滑滚动（popIn、hint 等一并停用） */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
  .slide-pop img { animation: none !important; }
}